Signal receiver having light guide for guiding light transmitted from remote control

Abstract

A signal receiver which receives an optical signal from a remote control includes a light guide for guiding a light passing through a front panel window toward a photodetector mounted on a circuit board. The light guide is made of a homogeneous material. A light guiding portion of the light guide extending from an entrance end to an exit end has a substantially circular cross section and is curved gently, not angularly. The exit end is configured to have a concave surface which is coaxial with the axes of both the cross section of the light guiding portion and a light-receptive portion of the photodetector. The exit end is disposed adjacent and opposite to the light-receptive portion.

1. An apparatus for receiving an optical signal from a remote control, comprising:
 a front panel provided with a window through which a light including the optical signal passes; 
 a circuit board disposed at substantially a right angle to the front panel; 
 a photodetector mounted on the circuit board in a manner that allows the photodetector to have a directionality in a normal direction on the circuit board; and 
 a light guide attached to the front panel for guiding the light passing through the window toward the photodetector; 
 wherein the light guide comprises homogenous material and guides the light with a boundary between an outer surface thereof and the atmosphere reflecting the light totally; 
 wherein a light guiding portion of the light guide extending from an entrance end of the light guide facing the window to an exit end of the light guide facing the photodetector has a substantially circular cross section and is curved gently and non-angularly such that the entrance end and the exit end are arranged substantially perpendicular to each other; 
 wherein the exit end includes a concave surface, is configured to be coaxial with and opposite to a shape of a light-receptive portion of the photodetector, and is adjacent to the light-receptive portion; 
 wherein a center of the exit end corresponds to a center of the photodetector in a plan view; and 
 wherein the photodetector comprises a substantially dome-shaped light-receptive portion, and the exit end of the light guide is coaxial with and opposite to the substantially dome-shaped light-receptive portion. 
 
   
   
     2. The apparatus for receiving an optical signal from a remote control according to  claim 1 , wherein the front panel is provided with a stand for holding the circuit board on the inside. 
   
   
     3. The apparatus for receiving an optical signal from a remote control according to  claim 1 , wherein the front panel comprises claws for engaging with the light guide; and
 wherein the light guide comprises a flange by which the light guide is attached to the front panel, the light guide being held by the front panel with the claws passing through corresponding holes provided at the flange. 
 
   
   
     4. The apparatus for receiving an optical signal from a remote control according to  claim 1 , wherein the light guide comprises a homogenous synthetic resin that is translucent and increased in refractive index relative to the atmosphere. 
   
   
     5. An apparatus for receiving an optical signal from a remote control, comprising:
 a front panel provided with a window through which a light including the optical signal passes; 
 a circuit board disposed at substantially a right angle to the front panel; 
 a photodetector having a substantially dome-shaped light-receptive portion mounted on the circuit board in a manner that allows the light-receptive portion to have a directivity in a normal direction on the circuit board; and 
 a light guide attached to the front panel for guiding the light passing through the window toward the photodetector, an entrance end of the light guide facing the window including a Fresnel lens structure, and an exit end of the light guide facing the photodetector including a concave surface; 
 wherein the light guide comprises homogenous material and guides the light with a boundary between an outer surface thereof and the atmosphere reflecting the light totally; 
 wherein a light guiding portion of the light guide extending from the entrance end to the exit end has a substantially circular cross section and is curved gently and non-angularly such that the entrance end and the exit end are arranged substantially perpendicular to each other; and 
 wherein the exit end is configured such that the concave surface is coaxial with axes of the cross section of the light guiding portion and the substantially dome-shaped light-receptive portion, and the exit end is adjacent and opposite to the light-receptive portion.